pinmux.c

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/*
 * Core driver for the pin muxing portions of the pin control subsystem
 *
 * Copyright (C) 2011-2012 ST-Ericsson SA
 * Written on behalf of Linaro for ST-Ericsson
 * Based on bits of regulator core, gpio core and clk core
 *
 * Author: Linus Walleij <[email protected]>
 *
 * Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved.
 *
 * License terms: GNU General Public License (GPL) version 2
 */
#define pr_fmt(fmt) "pinmux core: " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/radix-tree.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/pinctrl/machine.h>
#include <linux/pinctrl/pinmux.h>
#include "core.h"
#include "pinmux.h"

int pinmux_check_ops(struct pinctrl_dev *pctldev)
{
    const struct pinmux_ops *ops = pctldev->desc->pmxops;
    unsigned nfuncs;
    unsigned selector = 0;

    /* Check that we implement required operations */
    if (!ops ||
        !ops->get_functions_count ||
        !ops->get_function_name ||
        !ops->get_function_groups ||
        !ops->enable) {
        dev_err(pctldev->dev, "pinmux ops lacks necessary functions\n");
        return -EINVAL;
    }
    /* Check that all functions registered have names */
    nfuncs = ops->get_functions_count(pctldev);
    while (selector < nfuncs) {
        const char *fname = ops->get_function_name(pctldev,
                               selector);
        if (!fname) {
            dev_err(pctldev->dev, "pinmux ops has no name for function%u\n",
                selector);
            return -EINVAL;
        }
        selector++;
    }

    return 0;
}

int pinmux_validate_map(struct pinctrl_map const *map, int i)
{
    if (!map->data.mux.function) {
        pr_err("failed to register map %s (%d): no function given\n",
               map->name, i);
        return -EINVAL;
    }

    return 0;
}

static int pin_request(struct pinctrl_dev *pctldev,
               int pin, const char *owner,
               struct pinctrl_gpio_range *gpio_range)
{
    struct pin_desc *desc;
    const struct pinmux_ops *ops = pctldev->desc->pmxops;
    int status = -EINVAL;

    desc = pin_desc_get(pctldev, pin);
    if (desc == NULL) {
        dev_err(pctldev->dev,
            "pin %d is not registered so it cannot be requested\n",
            pin);
        goto out;
    }

    dev_dbg(pctldev->dev, "request pin %d (%s) for %s\n",
        pin, desc->name, owner);

    if (gpio_range) {
        /* There's no need to support multiple GPIO requests */
        if (desc->gpio_owner) {
            dev_err(pctldev->dev,
                "pin %s already requested by %s; cannot claim for %s\n",
                desc->name, desc->gpio_owner, owner);
            goto out;
        }

        desc->gpio_owner = owner;
    } else {
        if (desc->mux_usecount && strcmp(desc->mux_owner, owner)) {
            dev_err(pctldev->dev,
                "pin %s already requested by %s; cannot claim for %s\n",
                desc->name, desc->mux_owner, owner);
            goto out;
        }

        desc->mux_usecount++;
        if (desc->mux_usecount > 1)
            return 0;

        desc->mux_owner = owner;
    }

    /* Let each pin increase references to this module */
    if (!try_module_get(pctldev->owner)) {
        dev_err(pctldev->dev,
            "could not increase module refcount for pin %d\n",
            pin);
        status = -EINVAL;
        goto out_free_pin;
    }

    /*
     * If there is no kind of request function for the pin we just assume
     * we got it by default and proceed.
     */
    if (gpio_range && ops->gpio_request_enable)
        /* This requests and enables a single GPIO pin */
        status = ops->gpio_request_enable(pctldev, gpio_range, pin);
    else if (ops->request)
        status = ops->request(pctldev, pin);
    else
        status = 0;

    if (status) {
        dev_err(pctldev->dev, "request() failed for pin %d\n", pin);
        module_put(pctldev->owner);
    }

out_free_pin:
    if (status) {
        if (gpio_range) {
            desc->gpio_owner = NULL;
        } else {
            desc->mux_usecount--;
            if (!desc->mux_usecount)
                desc->mux_owner = NULL;
        }
    }
out:
    if (status)
        dev_err(pctldev->dev, "pin-%d (%s) status %d\n",
            pin, owner, status);

    return status;
}

static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
                struct pinctrl_gpio_range *gpio_range)
{
    const struct pinmux_ops *ops = pctldev->desc->pmxops;
    struct pin_desc *desc;
    const char *owner;

    desc = pin_desc_get(pctldev, pin);
    if (desc == NULL) {
        dev_err(pctldev->dev,
            "pin is not registered so it cannot be freed\n");
        return NULL;
    }

    if (!gpio_range) {
        desc->mux_usecount--;
        if (desc->mux_usecount)
            return NULL;
    }

    /*
     * If there is no kind of request function for the pin we just assume
     * we got it by default and proceed.
     */
    if (gpio_range && ops->gpio_disable_free)
        ops->gpio_disable_free(pctldev, gpio_range, pin);
    else if (ops->free)
        ops->free(pctldev, pin);

    if (gpio_range) {
        owner = desc->gpio_owner;
        desc->gpio_owner = NULL;
    } else {
        owner = desc->mux_owner;
        desc->mux_owner = NULL;
        desc->mux_setting = NULL;
    }

    module_put(pctldev->owner);

    return owner;
}

int pinmux_request_gpio(struct pinctrl_dev *pctldev,
            struct pinctrl_gpio_range *range,
            unsigned pin, unsigned gpio)
{
    const char *owner;
    int ret;

    /* Conjure some name stating what chip and pin this is taken by */
    owner = kasprintf(GFP_KERNEL, "%s:%d", range->name, gpio);
    if (!owner)
        return -EINVAL;

    ret = pin_request(pctldev, pin, owner, range);
    if (ret < 0)
        kfree(owner);

    return ret;
}

void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned pin,
              struct pinctrl_gpio_range *range)
{
    const char *owner;

    owner = pin_free(pctldev, pin, range);
    kfree(owner);
}

int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
              struct pinctrl_gpio_range *range,
              unsigned pin, bool input)
{
    const struct pinmux_ops *ops;
    int ret;

    ops = pctldev->desc->pmxops;

    if (ops->gpio_set_direction)
        ret = ops->gpio_set_direction(pctldev, range, pin, input);
    else
        ret = 0;

    return ret;
}

static int pinmux_func_name_to_selector(struct pinctrl_dev *pctldev,
                    const char *function)
{
    const struct pinmux_ops *ops = pctldev->desc->pmxops;
    unsigned nfuncs = ops->get_functions_count(pctldev);
    unsigned selector = 0;

    /* See if this pctldev has this function */
    while (selector < nfuncs) {
        const char *fname = ops->get_function_name(pctldev,
                               selector);

        if (!strcmp(function, fname))
            return selector;

        selector++;
    }

    pr_err("%s does not support function %s\n",
           pinctrl_dev_get_name(pctldev), function);
    return -EINVAL;
}

int pinmux_map_to_setting(struct pinctrl_map const *map,
              struct pinctrl_setting *setting)
{
    struct pinctrl_dev *pctldev = setting->pctldev;
    const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
    const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
    char const * const *groups;
    unsigned num_groups;
    int ret;
    const char *group;
    int i;
    const unsigned *pins;
    unsigned num_pins;

    if (!pmxops) {
        dev_err(pctldev->dev, "does not support mux function\n");
        return -EINVAL;
    }

    ret = pinmux_func_name_to_selector(pctldev, map->data.mux.function);
    if (ret < 0) {
        dev_err(pctldev->dev, "invalid function %s in map table\n",
            map->data.mux.function);
        return ret;
    }
    setting->data.mux.func = ret;

    ret = pmxops->get_function_groups(pctldev, setting->data.mux.func,
                      &groups, &num_groups);
    if (ret < 0) {
        dev_err(pctldev->dev, "can't query groups for function %s\n",
            map->data.mux.function);
        return ret;
    }
    if (!num_groups) {
        dev_err(pctldev->dev,
            "function %s can't be selected on any group\n",
            map->data.mux.function);
        return -EINVAL;
    }
    if (map->data.mux.group) {
        bool found = false;
        group = map->data.mux.group;
        for (i = 0; i < num_groups; i++) {
            if (!strcmp(group, groups[i])) {
                found = true;
                break;
            }
        }
        if (!found) {
            dev_err(pctldev->dev,
                "invalid group \"%s\" for function \"%s\"\n",
                group, map->data.mux.function);
            return -EINVAL;
        }
    } else {
        group = groups[0];
    }

    ret = pinctrl_get_group_selector(pctldev, group);
    if (ret < 0) {
        dev_err(pctldev->dev, "invalid group %s in map table\n",
            map->data.mux.group);
        return ret;
    }
    setting->data.mux.group = ret;

    ret = pctlops->get_group_pins(pctldev, setting->data.mux.group, &pins,
                      &num_pins);
    if (ret) {
        dev_err(pctldev->dev,
            "could not get pins for device %s group selector %d\n",
            pinctrl_dev_get_name(pctldev), setting->data.mux.group);
            return -ENODEV;
    }

    /* Try to allocate all pins in this group, one by one */
    for (i = 0; i < num_pins; i++) {
        ret = pin_request(pctldev, pins[i], map->dev_name, NULL);
        if (ret) {
            dev_err(pctldev->dev,
                "could not request pin %d on device %s\n",
                pins[i], pinctrl_dev_get_name(pctldev));
            /* On error release all taken pins */
            i--; /* this pin just failed */
            for (; i >= 0; i--)
                pin_free(pctldev, pins[i], NULL);
            return -ENODEV;
        }
    }

    return 0;
}

void pinmux_free_setting(struct pinctrl_setting const *setting)
{
    struct pinctrl_dev *pctldev = setting->pctldev;
    const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
    const unsigned *pins;
    unsigned num_pins;
    int ret;
    int i;

    ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
                      &pins, &num_pins);
    if (ret) {
        dev_err(pctldev->dev,
            "could not get pins for device %s group selector %d\n",
            pinctrl_dev_get_name(pctldev), setting->data.mux.group);
        return;
    }

    for (i = 0; i < num_pins; i++)
        pin_free(pctldev, pins[i], NULL);
}

int pinmux_enable_setting(struct pinctrl_setting const *setting)
{
    struct pinctrl_dev *pctldev = setting->pctldev;
    const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
    const struct pinmux_ops *ops = pctldev->desc->pmxops;
    int ret;
    const unsigned *pins;
    unsigned num_pins;
    int i;
    struct pin_desc *desc;

    ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
                      &pins, &num_pins);
    if (ret) {
        /* errors only affect debug data, so just warn */
        dev_warn(pctldev->dev,
             "could not get pins for group selector %d\n",
             setting->data.mux.group);
        num_pins = 0;
    }

    for (i = 0; i < num_pins; i++) {
        desc = pin_desc_get(pctldev, pins[i]);
        if (desc == NULL) {
            dev_warn(pctldev->dev,
                 "could not get pin desc for pin %d\n",
                 pins[i]);
            continue;
        }
        desc->mux_setting = &(setting->data.mux);
    }

    return ops->enable(pctldev, setting->data.mux.func,
               setting->data.mux.group);
}

void pinmux_disable_setting(struct pinctrl_setting const *setting)
{
    struct pinctrl_dev *pctldev = setting->pctldev;
    const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
    const struct pinmux_ops *ops = pctldev->desc->pmxops;
    int ret;
    const unsigned *pins;
    unsigned num_pins;
    int i;
    struct pin_desc *desc;

    ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
                      &pins, &num_pins);
    if (ret) {
        /* errors only affect debug data, so just warn */
        dev_warn(pctldev->dev,
             "could not get pins for group selector %d\n",
             setting->data.mux.group);
        num_pins = 0;
    }

    for (i = 0; i < num_pins; i++) {
        desc = pin_desc_get(pctldev, pins[i]);
        if (desc == NULL) {
            dev_warn(pctldev->dev,
                 "could not get pin desc for pin %d\n",
                 pins[i]);
            continue;
        }
        desc->mux_setting = NULL;
    }

    if (ops->disable)
        ops->disable(pctldev, setting->data.mux.func, setting->data.mux.group);
}

#ifdef CONFIG_DEBUG_FS

/* Called from pincontrol core */
static int pinmux_functions_show(struct seq_file *s, void *what)
{
    struct pinctrl_dev *pctldev = s->private;
    const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
    unsigned nfuncs;
    unsigned func_selector = 0;

    if (!pmxops)
        return 0;

    mutex_lock(&pinctrl_mutex);
    nfuncs = pmxops->get_functions_count(pctldev);
    while (func_selector < nfuncs) {
        const char *func = pmxops->get_function_name(pctldev,
                              func_selector);
        const char * const *groups;
        unsigned num_groups;
        int ret;
        int i;

        ret = pmxops->get_function_groups(pctldev, func_selector,
                          &groups, &num_groups);
        if (ret)
            seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
                   func);

        seq_printf(s, "function: %s, groups = [ ", func);
        for (i = 0; i < num_groups; i++)
            seq_printf(s, "%s ", groups[i]);
        seq_puts(s, "]\n");

        func_selector++;
    }

    mutex_unlock(&pinctrl_mutex);

    return 0;
}

static int pinmux_pins_show(struct seq_file *s, void *what)
{
    struct pinctrl_dev *pctldev = s->private;
    const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
    const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
    unsigned i, pin;

    if (!pmxops)
        return 0;

    seq_puts(s, "Pinmux settings per pin\n");
    seq_puts(s, "Format: pin (name): mux_owner gpio_owner hog?\n");

    mutex_lock(&pinctrl_mutex);

    /* The pin number can be retrived from the pin controller descriptor */
    for (i = 0; i < pctldev->desc->npins; i++) {
        struct pin_desc *desc;
        bool is_hog = false;

        pin = pctldev->desc->pins[i].number;
        desc = pin_desc_get(pctldev, pin);
        /* Skip if we cannot search the pin */
        if (desc == NULL)
            continue;

        if (desc->mux_owner &&
            !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev)))
            is_hog = true;

        seq_printf(s, "pin %d (%s): %s %s%s", pin,
               desc->name ? desc->name : "unnamed",
               desc->mux_owner ? desc->mux_owner
                : "(MUX UNCLAIMED)",
               desc->gpio_owner ? desc->gpio_owner
                : "(GPIO UNCLAIMED)",
               is_hog ? " (HOG)" : "");

        if (desc->mux_setting)
            seq_printf(s, " function %s group %s\n",
                   pmxops->get_function_name(pctldev,
                    desc->mux_setting->func),
                   pctlops->get_group_name(pctldev,
                    desc->mux_setting->group));
        else
            seq_printf(s, "\n");
    }

    mutex_unlock(&pinctrl_mutex);

    return 0;
}

void pinmux_show_map(struct seq_file *s, struct pinctrl_map const *map)
{
    seq_printf(s, "group %s\nfunction %s\n",
        map->data.mux.group ? map->data.mux.group : "(default)",
        map->data.mux.function);
}

void pinmux_show_setting(struct seq_file *s,
             struct pinctrl_setting const *setting)
{
    struct pinctrl_dev *pctldev = setting->pctldev;
    const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
    const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;

    seq_printf(s, "group: %s (%u) function: %s (%u)\n",
           pctlops->get_group_name(pctldev, setting->data.mux.group),
           setting->data.mux.group,
           pmxops->get_function_name(pctldev, setting->data.mux.func),
           setting->data.mux.func);
}

static int pinmux_functions_open(struct inode *inode, struct file *file)
{
    return single_open(file, pinmux_functions_show, inode->i_private);
}

static int pinmux_pins_open(struct inode *inode, struct file *file)
{
    return single_open(file, pinmux_pins_show, inode->i_private);
}

static const struct file_operations pinmux_functions_ops = {
    .open       = pinmux_functions_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};

static const struct file_operations pinmux_pins_ops = {
    .open       = pinmux_pins_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};

void pinmux_init_device_debugfs(struct dentry *devroot,
             struct pinctrl_dev *pctldev)
{
    debugfs_create_file("pinmux-functions", S_IFREG | S_IRUGO,
                devroot, pctldev, &pinmux_functions_ops);
    debugfs_create_file("pinmux-pins", S_IFREG | S_IRUGO,
                devroot, pctldev, &pinmux_pins_ops);
}

#endif /* CONFIG_DEBUG_FS */